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1
Ivan, M., T. Entz, P. S. Mir, Z. Mir, and T. A. McAllister. "Effects of sunflower seed supplementation and different dietary protein concentrations on the ciliate protozoa population dynamics in the rumen of sheep." Canadian Journal of Animal Science 83, no. 4 (2003): 809–17. http://dx.doi.org/10.4141/a03-052.
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The effects of feeding a linoleic acid-rich sunflower seed supplement and different levels of dietary protein on protozoal numbers and fermentation parameters in rumen fluid were determined in an 84-d experiment with rumen-cannulated sheep. The experiment comprised four treatments, two with low crude protein diets [12% of dietary dry matter (DM)] and two with high protein diets (16% of DM). On both low and high protein diets, one treatment was without (Control) and one with the sunflower seed (high linoleic acid variety 6150) supplement (14% of dietary DM). The four diets used were based on corn silage and corn grain, and soybean meal was used to achieve the desired concentration of dietary protein. The sheep were fully fed each morning and rumen fluid samples were taken 2 h later on various days of the experiment (daily during the first 14 d for enumeration of protozoa). In addition, rumen fluid was sampled at different hours after feeding on day 43 of the experiment. Results showed a protozoa-decreasing effect (P < 0.001) of sunflower seeds causing a decline in protozoa numbers after 2 d of supplementation. The effect of protein on protozoa numbers was dependent on the presence of sunflower seed supplement. Measurements on day 43 showed increased protozoa numbers (P < 0.05) and ammonia nitrogen concentrations (P < 0.001) due to higher dietary protein, and decreased protozoal numbers (P < 0.05) and ammonia nitrogen (P < 0.001) due to the sunflower seed supplement, without significant effects (P > 0.05) on volatile fatty acid concentrations. The linoleic acid-rich sunflower seed supplement was highly effective in reducing both protozoa numbers and ammonia nitrogen concentrations in rumen fluid. Key words: Rumen ciliate protozoa, sunflower seeds, dietary protein, sheep
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Salles, Márcia Saladini Vieira, Suelen Correa Silva, Luiz Carlos Roma, et al. "Detection of heat produced during roughage digestion in ruminants by using infrared thermography." Animal Production Science 58, no. 11 (2018): 2032. http://dx.doi.org/10.1071/an16011.
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The present study aimed to establish the relationship of infrared thermography (IRT) with fermentation dynamics in ruminants, and to initiate the development of a method that allows associating these images with the heat produced during feed digestion. The experiment was conducted at APTA, Brazil. Twenty-four Jersey heifers (mean liveweight of 221.25 ± 59.41 kg) were subjected to the following treatments: 30R (30% corn silage and 70% concentrate), 50R (50% corn silage and 50% concentrate) and 70R (70% corn silage and 30% concentrate) in a Latin square design. The diet (corn silage + concentrate) was offered at 3% of liveweight from 0800 hours to 1400 hours. Infrared images were collected from the whole body on the left and right sides, from the eyes, from the left foreleg on the cranial and caudal side, and from the forehead. IRT images were taken at 2-h intervals for 12 h (from 0600 hours to 1800 hours) and 24 h (0600 hours of the following day) after the beginning of feeding and so on. Physiological parameters were obtained at the same time as the IRT were taken. Ruminal parameters were collected after 4 h of feeding. The thermograms of the right (P < 0.001) and left flank (P < 0.001) differed among sampling times, with an increase in temperature until 1400 hours and a reduction thereafter. The temperatures on the right (P = 0.037) and left (P = 0.017) flank were higher in animals consuming the 50R diet and lower in those consuming the 70R diet. When the 50R diet was offered, the heifers exhibited higher dry-matter intake (P < 0.001), neutral detergent fibre (P < 0.001), non-fibrous carbohydrates (P < 0.001) and total digestible nutrients (P < 0.001). A decrease in the concentrations of butyric acid (P = 0.042), isobutyric acid (P = 0.001), isovaleric acid (P = 0.019) and ammonia nitrogen (P = 0.001) in the rumen fluid of heifers was observed with an increasing dietary roughage level. Infrared thermography was able to detect differences in the body temperature of animals associated with different fibre proportions in the diets. However, the magnitude of these differences was small and further research is needed to investigate the application of IRT to the detection of possible differences in the body temperature of ruminants as part of the digestive process.
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Cobb, Bonnie F., Joseph Kallenbach, Clifford A. Hall, and Scott W. Pryor. "Optimizing the Supercritical Fluid Extraction of Lutein from Corn Gluten Meal." Food and Bioprocess Technology 11, no. 4 (2018): 757–64. http://dx.doi.org/10.1007/s11947-017-2052-7.
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Gvozdenac, D. D. "Analytical Solution of the Transient Response of Gas-to-Gas Crossflow Heat Exchanger With Both Fluids Unmixed." Journal of Heat Transfer 108, no. 4 (1986): 722–27. http://dx.doi.org/10.1115/1.3247004.
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The dynamic response of a single-pass crossflow heat exchanger with both fluids unmixed to arbitrary time varying inlet temperatures of fluids is investigated analytically. The initial spatial temperature distribution of the heat exchanger core is arbitrary as well. Analytical solutions for temperature distributions of both fluids and the wall as well as the mean mixed fluid temperatures at the exit are presented. The solutions are found by using Laplace transform method and special functions in the form of series of modified Bessel functions.
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Xiaohua, Li, Zheng Guo, Grecov Dana, and Zhongxi Hou. "Efficient reduced-order modeling of unsteady aerodynamics under light dynamic stall conditions." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 6 (2018): 2141–51. http://dx.doi.org/10.1177/0954410018773628.
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In this research, a reduced-order modeling is developed to predict the unsteady aerodynamic forces under light dynamic stall conditions at low-speed regimes. The filtered white Gaussian noise is selected as input signals for computational fluid dynamics solver in order to generate training data, containing the information of reduced frequency and amplitude. Because of the time history influences, the reduced-order modeling combines the Kriging function and recurrence framework together in this approach. An airfoil NACA0012 undergoing pitching motions with different reduced frequency, amplitude, and mean angle of attack is designed to illustrate the methodology. The developed model can predict the lift, drag, and moment coefficients in seconds on a single-core computer processor. To reduce the prediction errors between reduced-order modeling predictions and computational fluid dynamics simulations, the aerodynamic loads in static conditions are applied as initial inputs. The predictions via the proposed approach are in agreement with the results using a high precision computational fluid dynamics solver over the designed ranges of amplitude and reduced frequency, which is suitable for engineering applications, such as fluid-structure interaction, and aircraft design optimizations.
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Giddings, D., C. N. Eastwick, S. J. Pickering, and K. Simmons. "Computational fluid dynamics applied to a cement precalciner." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, no. 3 (2000): 269–80. http://dx.doi.org/10.1243/0957650001538353.
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This paper describes a study of the use of computational fluid dynamics (CFD) to investigate the performance of a precalciner vessel at a cement works, In this vessel, limestone, held in suspension, is calcined to calcium oxide and the endothermic reaction is supported by the combustion of coal. Results are presented from a CFD model that contains all the essential features of the precalciner as operated when burning coal. The model fully represents the reactions and fluid dynamics of the precalciner. Previously unidentified features are illustrated. Certain key features at points in the precalciner, where some limited measurements can be made, are compared with the parameters indicated by the computational model. The measurements are consistent with the results calculated by the model indicating fair validation. The CFD data show the following 1 The gases undergo distinct recirculation. 2 The coal particles entering at one inlet have significantly different trajectories and temperature histories from those entering at the second diametrically opposed inlet. 3 There is 90 per cent completion of coal combustion at the exit. 4 73 per cent limestone in the raw meal is calcined to calcined to calcium oxide at the exit from the precalciner. 5 The highest reaction rate of the raw meal is closer to one side of the vessel due to interaction with the gas flows. Future work is proposed which, firstly, will provide further validation of the results so far attained by selective measurements on the precalciner and, secondly, will model the combustion and aerodynamic behaviour of waste-derived fuels in the precalciner vessel, commencing with shredded car tyre chips.
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MAHADEVAN, S., F. D. SAUER, and J. D. ERFLE. "PREPARATION OF PROTEASE FROM MIXED RUMEN MICROORGANISMS AND ITS USE FOR THE IN VITRO DETERMINATION OF THE DEGRADABILITY OF TRUE PROTEIN IN FEEDSTUFFS." Canadian Journal of Animal Science 67, no. 1 (1987): 55–64. http://dx.doi.org/10.4141/cjas87-007.
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Mixed rumen microorganisms present in bovine rumen fluid were extracted with butanol-acetone to provide a dry powder which retained 75–80% of the proteolytic activity of strained rumen fluid (SRF). Sixty percent of the proteolytic activity of the powder was extracted with water and concentrated on an Amicon XM-300 filter to give a protease preparation which had about 30% of the activity present in the SRF. The protease preparation was used for the determination of the rates of feed protein degradation in vitro by incubating at pH 6.8 in 0.1 M potassium phosphate buffer and measuring the rate of amino acid (and ammonia) production by the ninhydrin method. The relative degradation rates of the true proteins from feedstuffs tested were: soybean meal > fish meal > linseed meal and blood meal > canola meal > corn gluten meal. Substituting Streptomyces griseus protease for the rumen protease gave results which were very different from those obtained with the rumen enzyme. The advantages of using the rumen protease over other in vitro methods and the practical applicability of the procedure are discussed. Key words: Rumen, protease, preparation, in vitro, feed protein degradability
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O'Hara, A. S., A. Tanner, T. A. McAllister, D. J. Gibb, F. van Herk, and A. V. Chaves. "Effect of low and high oil corn distillers' grain on rumen fermentation, growth performance and carcass characteristics of lambs." Animal Production Science 51, no. 8 (2011): 708. http://dx.doi.org/10.1071/an11023.
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The objective of this study was to determine the effect of replacing a mixture of canola meal and barley grain in the diet with (low and high oil) corn dried distillers’ grains with solubles (DDGS) or wheat DDGS on rumen fermentation, feed intake, growth performance and carcass traits in lambs. Seventy Canadian Arcott lambs (24.7 ± 3.21 kg) were used in a completely randomised block design over a 14-week trial. Experimental diets were provided ad libitum as pelleted total mixed rations. In the treatment diets, canola meal and barley grain were replaced with 200 g/kg of dietary DM of either high oil corn DDGS, low oil corn DDGS or wheat DDGS. A positive control diet was added to match the lipid content of 39 g/kg DM of the high oil corn DDGS diet. An in vitro rumen digestibility trial was conducted using ruminal fluid obtained from three non-lactating Holstein dairy cows. Rumen contents were also collected from each lamb at the time of slaughter for testing in vivo rumen fermentation. Data from both the in vivo and in vitro results were analysed using the MIXED procedure of SAS. The in vitro incubations revealed both corn DDGS diets produced less microbial N and microbial DM than control and wheat DDGS diets; however, this difference was too minimal to affect growth performance. Similarly, there was no dietary effect on (P > 0.05) on in vivo ruminal fermentation or carcass characteristics (P ≥ 0.19) of the lambs. Lambs fed low oil corn DDGS had lower average daily gains (P < 0.03) than those fed either high oil corn DDGS or wheat DDGS however they did not differ from those fed the control. This research demonstrated that replacing canola meal and portions of barley grain with 200 g/kg DM of either high oil corn DDGS, low oil corn DDGS or wheat DDGS in finishing lamb ratios could effectively maintain healthy rumen function, growth performance and carcass characteristics.
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McKeown, L. E., A. V. Chaves, M. Oba, M. E. R. Dugan, E. Okine, and T. A. McAllister. "Effects of corn-, wheat- or triticale dry distillers’ grains with solubles on in vitro fermentation, growth performance and carcass traits of lambs." Canadian Journal of Animal Science 90, no. 1 (2010): 99–108. http://dx.doi.org/10.4141/cjas09084.
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The objective of this study was to determine the effect of replacing a mixture of canola meal and barley grain with corn-, wheat- or triticale dry distillers’ grains with solubles (DDGS) at 20% of dietary dry matter (DM) on in vitro ruminal fermentation in bovine ruminal fluid and on growth performance and carcass characteristics of lambs. Sixty ram lambs (22.6 ± 3.0 kg) were randomly assigned to one of four dietary treatments and given individual ad libitum access to feed until they attained slaughter weight. The control diet consisted (DM basis) of 54% barley grain, 16% sunflower hulls, 11.5% beet pulp, 10% canola meal, 2.5% canola oil and 6.0% molasses, vitamins and minerals mixture. For the three DDGS dietary treatments, 10% barley grain and 10% canola meal were replaced with 20% corn-, wheat-or triticale-DDGS. The source of DDGS did not influence (P > 0.51) dry matter intake (DMI) or average daily gain (ADG). Feed conversion (feed:gain) of lambs fed wheat DDGS was approx. 12% poorer (P < 0.05) than that of lambs fed control or corn DDGS diets. In vitro data suggest that the inefficient gain may have been attributable to greater (P < 0.05) ammonia concentration at 24 h and lower digestibility of wheat DDGS. Carcass traits, including hot carcass weight, body wall thickness and saleable meat yield, were not affected (P > 0.60) by dietary treatment. Total saturated, monounsaturated and polyunsaturated fatty acids in subcutaneous fat were also not affected by DGGS source (P ≥ 0.13). There was no treatment effect (P = 0.33) on concentrations of t11-18:1, but feeding triticale DDGS increased the concentration (P = 0.04) of c9, t11-conjugated linoleic acid (CLA). In conclusion, DDGS from corn, wheat or triticale can replace a mixture of barley grain and canola meal at 20% of dietary DM without adversely affecting DMI, ADG or carcass characteristics of growing lambs, although wheat DDGS may reduce feed conversion ratio (feed:gain). Including triticale DDGS may also improve the fatty acid profile of subcutaneous fat.Key words: Lamb, corn, wheat, triticale, distillers’ grains, performance, carcass characteristics
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Peixoto, Eduardo Lucas Terra, Mirton José Frota Morenz, Carlos Elysio Moreira da Fonseca, et al. "Citrus pulp in lamb diets: intake, digestibility, and ruminal parameters." Semina: Ciências Agrárias 36, no. 5 (2015): 3421. http://dx.doi.org/10.5433/1679-0359.2015v36n5p3421.
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<p>This study aimed to evaluate the viability of replacing corn meal with citrus pulp (0, 25, 50, 75, and 100 % dry matter of corn meal) by evaluating several nutritional parameters such as intake and digestibility of nutrients, and ruminal fermentation parameters. The diets were formulated to be isoproteic with a roughage:concentrate ratio of 60:40. Five crossbred lambs with an initial average weight of 26.1 ± 1.8 kg were used and distributed in a 5 x 5 Latin Square design. For digestibility of nutrients was carried out to feed, orts, and feces collection. The evaluated nutrients were dry matter, crude protein, ether extract, ash, neutral detergent fiber, fiber acid detergent and lignin. Were determined nitrogen and carbohydrate fractions, and ruminal fermentation parameters (N-NH 3 and ruminal pH). The results were subjected to analysis of variance and regression analysis (t-test; ? = 0.05). Citrus pulp inclusion in the diets did not affect intake and digestibility of nutrients, or the pH and the NH3-N content of the rumen fluid. Citrus pulp can be used as a total substitute for corn in concentrate or up to 26.5% in the total ration for lambs (dry basis). </p>
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Wood, Garnett E. "Aflatoxins in Domestic and Imported Foods and Feeds." Journal of AOAC INTERNATIONAL 72, no. 4 (1989): 543–48. http://dx.doi.org/10.1093/jaoac/72.4.543.
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Abstract Aflatoxins, metabolic products of the molds Aspergillus flams and A. parasiticus, may occur in foods and feeds. These toxins cannot be entirely avoided or eliminated from foods or feeds by current agronomic and manufacturing processes and are considered unavoidable contaminants. To limit aflatoxin exposure, the U.S. Food and Drug Administration (FDA) has set action levels for these toxins in foods and feeds involved in interstate commerce. FDA continually monitors food and feed industries through compliance programs. This report summarizes data generated from compliance programs on aflatoxins for the fiscal year 1986. Commodities sampled included peanuts and peanut products, corn and corn products, tree nuts, cottonseed, milk, spices, manufactured products, and miscellaneous foods and feeds. Correlations were highest between aflatoxin contamination and geographical areas for corn/corn products and cottonseed/cottonseed meal. Higher incidences of aflatoxin contamination in corn and corn products designated for human consumption were observed in samples collected in the southeastern states (32 and 28%, respectively). A higher incidence of contamination was observed in corn designated for animal feed from Arkansas-Texas (74%) than from the southeastern states (47%). Only 3% of feed corn from corn belt states contained detectable aflatoxins. All aflatoxin-contaminated cottonseed was collected in the Arizona-California area; 80% of cottonseed meal analyzed from this area also contained detectable levels of aflatoxins. No aflatoxin Mi was detected in any of the 182 samples of fluid milk and milk products examined. The percentage of samples that contain measurable levels of aflatoxins is expected to vary with commodities from year to year; thus, the 1986 information can be used as a baseline for comparison to determine the effectiveness of control efforts exerted by the food and feed industries.
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Landau, S., JA Houghton, JR Mawhinney, and EK Inskeep. "Protein sources affect follicular dynamics in ewes near the onset of the breeding season." Reproduction, Fertility and Development 8, no. 6 (1996): 1021. http://dx.doi.org/10.1071/rd9961021.
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The influence of source of protein during the luteal phase before a synchronized oestrus on the dynamics of follicular development, observed daily by ultrasonography, was assessed in ewes that were beginning the sexual season. Iso-nitrogenous amounts of soybean meal (SBM) or of a corn-gluten meal-ground-corn grain mixture (CGM-GC), or an iso-energetic amount of ground-corn grain (GC), were fed from four days before to four days after treatment with prostaglandin F2 alpha (PGF2 alpha). Feeding with SBM was associated with a higher frequency of short luteal phases (P < 0.02). Dynamics of follicular population were studied in ewes that ovulated after normal cycles. More follicles > or = 2 mm in diameter were observed on the ovaries of ewes fed SBM four days before PGF2 alpha treatment (P < 0.02), but the highest number was seen in ewes fed CGM-GC at the time of injection of PGF2 alpha (P < 0.08). Ewes fed SBM had larger follicles at last detection and ovulated earlier after PGF2 alpha treatment than their counterparts fed other diets (P < 0.001). Ovulatory follicles developed over a greater range of days in ewes with twin ovulations compared with ewes with single ovulations (P < 0.08). Serum concentrations of insulin were increased after four days of feeding with CGM-GC (P < 0.01), but not with SBM or GC, and reached a peak at the time of oestrus. In summary: (1) the source of dietary protein during the late-luteal phase affected follicular maturation after PGF2 alpha treatment; (2) insulin and glucose may be involved in this response and may play a role in ovarian follicular activity; and (3) twin ovulations appeared to result from both reduced atresia and increased recruitment of follicles.
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Song, M. K., and J. J. Kennelly. "Effects of ammonia concentration and microbial population on in vitro degradation of 14C-labelled dietary proteins." Canadian Journal of Animal Science 71, no. 1 (1991): 125–33. http://dx.doi.org/10.4141/cjas91-014.
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Rumen fluid from two nonlactating cows fed barley silage and rolled barley grain based concentrates (75:25 on a dry matter basis) was incubated for 0.5, 1, 2, 3, and 4 h with 14C-labelled soybean meal (SBM), fish meal (FM) and corn gluten meal (CGM) to examine the effects of ammonia concentration and protein solubility on rate and extent of protein degradation by total mixed ruminal microorganisms (TMM) or mixed ruminal bacteria (MB). Proteins were labelled by reductive methylation. Ammonia concentration in control ruminal fluid was 4.0 mg dL−1; graded levels of 1 M (NH4)2SO4 were added to achieve ammonia concentrations of 10, 20, and 30 mg dL−1 ruminal fluid. Soluble protein was extracted with borate-phosphate buffer (pH 7.8). Removal of protozoa reduced the extent of protein degradation. However, relative to bacteria, protozoa appeared to play a minor role in protein degradation. Rate and extent of protein degradation was not influenced by ammonia concentration, but was highly correlated with protein solubility. Therefore, it is concluded that ammonia concentration is not the primary factor regulating proteolytic activity of rumen microorganisms, rather their activities may depend upon the solubility and physico-chemical properties of proteins. Key words: In vitro, ammonia concentration, protein degradation, microbial population
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Schaefer-Rolffs, Urs, and Erich Becker. "Horizontal Momentum Diffusion in GCMs Using the Dynamic Smagorinsky Model." Monthly Weather Review 141, no. 3 (2013): 887–99. http://dx.doi.org/10.1175/mwr-d-12-00101.1.
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Abstract A dynamic version of Smagorinsky’s diffusion scheme is presented that is applicable for large-eddy simulations (LES) of the atmospheric dynamics. The approach is motivated (i) by the incompatibility of conventional hyperdiffusion schemes with the conservation laws, and (ii) because the conventional Smagorinsky model (which fulfills the conservation laws) does not maintain scale invariance, which is mandatory for a correct simulation of the macroturbulent kinetic energy spectrum. The authors derive a two-dimensional (horizontal) formulation of the dynamic Smagorinsky model (DSM) and present three solutions of the so-called Germano identity: the method of least squares, a solution without invariance of the Smagorinsky parameter, and a tensor-norm solution. The applicability of the tensor-norm approach is confirmed in simulations with the Kühlungsborn mechanistic general circulation model (KMCM). The standard spectral dynamical core of the model facilitates the implementation of the test filter procedure of the DSM. Various energy spectra simulated with the DSM and the conventional Smagorinsky scheme are presented. In particular, the results show that only the DSM allows for a reasonable spectrum at all scales. Latitude–height cross sections of zonal-mean fluid variables are given and show that the DSM preserves the main features of the atmospheric dynamics. The best ratio for the test-filter scale to the resolution scale is found to be 1.33, resulting in dynamically determined Smagorinsky parameters cS from 0.10 to 0.22 in the troposphere. This result is very similar to other values of cS found in previous three-dimensional applications of the DSM.
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Gao, Qingtao, Feng Zhao, Fangkun Dang, Hu Zhang, and Ya Wang. "Effect of Corn Particle Size on the Particle Size of Intestinal Digesta or Feces and Nutrient Digestibility of Corn–Soybean Meal Diets for Growing Pigs." Animals 10, no. 5 (2020): 876. http://dx.doi.org/10.3390/ani10050876.
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This study was conducted to evaluate the effect of corn particle size on the particle size of intestinal digesta or feces and nutrient digestibility of corn–soybean meal diets. Twenty-four growing barrows (initial BW: 21.9 ± 1.62 kg) were randomly divided into 4 groups of 6 pigs. A T-cannula was surgically placed in the anterior duodenum (about 50 cm from pylorus) of pigs in Groups 1 and 2 or in the distal ileum of pigs in Groups 3 and 4. Corn used to formulate diets had mean particle size (MPS) of 365 µm (Corn 1) or 682 µm (Corn 2), resulting in diets with MPS of 390 µm (Diet 1) or 511 μm (Diet 2). Diet 1 or 2 were randomly assigned within pig Groups 1 or 2 and 3 or 4. The digestive enzyme activities of duodenal fluid, particle size of intestinal digesta and feces, as well as nutrient digestibility, were determined for each pig as the experiment unit. The MPS of duodenal digesta (181 vs. 287 µm, p < 0.01), ileal digesta (253 vs. 331 µm, p < 0.01), and feces (195 vs. 293 µm, p < 0.01) was significantly reduced for pigs fed Diet 1 vs. Diet 2, respectively. Compared with Diet 2, Diet 1 significantly reduced the proportion of particles above 0.5 mm, but significantly increased the proportion of particles between 0.072 and 0.5 mm (p < 0.01) in digesta and feces (p < 0.01). Diet 1 significantly increased solubles percentage (<0.072 mm) in duodenal digesta (p < 0.05) but did not affect solubles percentage in ileal digesta and feces. The MPS of diet did not affect the activities of amylase, trypsin, and chymotrypsin in the duodenal fluid and the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein, ether extract, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in pigs offered Diet 1 compared to Diet 2. The in vitro digestible energy (IVDE) (3706 vs. 3641 kcal/kg; p = 0.03) was greater for Corn 1 vs. Corn 2. However, no significant difference was observed in IVDE (3574 vs. 3561 kcal/kg; p = 0.47) for Diet 1 vs. Diet 2. In conclusion, the particle size of digesta and feces was dependent on the dietary particle size. However, the digestive enzyme activities of duodenal fluid and ATTD of energy and nutrients were not affected by reducing dietary MPS from 511 to 390 µm.
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Hambakodu, Marselinus, and Yessy Tamu Ina. "Evaluasi Kecernaan In Vitro Bahan Pakan Hasil Samping Agro Industri." Jurnal Agripet 19, no. 1 (2019): 7–12. http://dx.doi.org/10.17969/agripet.v19i1.12953.
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ABSTRAK. Penelitian ini bertujuan untuk mengevaluasi nilai kecernaan bahan kering, kecernaan bahan organik dan nilai TDN bahan pakan hasil samping agro industry. Evaluasi dilakukan secara in vitro menggunakan cairan rumen kambing Peranakan Ettawa dengan pakan PK 12% dan TDN 62%. Penelitian menggunakan metode eksperimental rancangan acak lengkap 7 perlakuan dan 3 ulangan. Pakan perlakuan terdiri atas ampas tahu, bungkil kopra, bungkil kelapa sawit, bungkil kedelai, onggok, kulit kopi, dan janggel jagung. Data dianalisis menggunakan ANOVA dan n uji lanjut Duncan. Hasil penelitian menunjukkan adanya perbedaan kecernaan bahan kering, kecernaan bahan organik dan nilai TDN (P0,05) antara bahan pakan hasil samping agro industri. Ampas tahu memiliki kecernaan bahan kering (73,03%), kecernaan bahan organik (71,66%), dan nilai TDN (71,88%) lebih tinggi dibanding bungkil kopra, bungkil kelapa sawit, bungkil kedelai, onggok, janggel jagung dan kulit kopi. (In vitro digestibility evaluation of feed ingredients from agro-industry by-product) ABSTRACT. This study aimed to evaluate the value of dry matter-, organic matter digestibility and TDN of feed ingredients from agro-industrial by product. In vitro evaluation using rumen fluid of Ettawa crossbreed goat feeding with 12% PK and 62% TDN. The experimental used a completely randomized design with 7 treatments and 3 replications. The feed treatments were tofu waste, coconut meal, palm kernel meal, soybean meal, onggok, coffee husk, and corn cob. Data were analyzed using ANOVA and continued by Duncan test. The results showed differences in dry matter digestibility, organic matter digestibility and TDN value (P 0.05) between feed ingredients from agro-industrial by product. Tofu waste has dry matter digestibility (73.03%), organic matter digestibility (71.66%), and TDN value (71.88%) higher than coconut meal, palm kernel meal, soybean meal, onggok, corn cob and coffee husk.
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SONG, M. K., and J. J. KENNELLY. "IN SITU DEGRADATION OF FEED INGREDIENTS, FERMENTATION PATTERN AND MICROBIAL POPULATION AS INFLUENCED BY RUMINAL AMMONIA CONCENTRATION." Canadian Journal of Animal Science 69, no. 4 (1989): 999–1006. http://dx.doi.org/10.4141/cjas89-114.
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Effects of ruminal ammonia concentration on ruminal parameters and in situ degradation of feed ingredients were examined with nonlactating Holstein cows fed a complete mixed diet (70% barley silage and 30% concentrate mixture, dry matter (DM) basis). Ruminal ammonia concentrations of 16.3, 24.8 and 34.9 mg 100 mL−1 were achieved by continuous intraruminal infusions of NH4Cl. Ammonia concentrations in control animals were 11.2 mg 100 mL−1. Ruminal fluid pH decreased (P < 0.05) and blood urea N increased (P < 0.05) with NH4Cl infusion. NH4Cl infusion increased (P < 0.05) viable counts of proteolytic bacteria. Effective degradability of dry matter (EDDM) of concentrate ingredients and crude protein (EDCP) of soybean meal and fish meal were not affected by NH4Cl infusion. But EDCP of corn gluten meal was highest (P < 0.05) at ammonia concentration of 16.3 mg 100 mL−1 rumen fluid and EDDM and neutral detergent fiber (EDNDF) of barley silage decreased (P < 0.05) with increasing NH4Cl infusion. Results are interpreted to indicate that ruminal ammonia concentrations necessary for maximal bacterial growth may differ from concentrations required for maximal degradation of feedstuffs. However, decreased pH associated with NH4Cl infusion may have influenced the results obtained. Key words: Ammonia concentration, bacterial growth, in situ degradation
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Mukherjee, Debraj, Barry D. Pressman, Deborah Krakow, David L. Rimoin, and Moise Danielpour. "Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series." Journal of Neurosurgery: Pediatrics 14, no. 3 (2014): 238–44. http://dx.doi.org/10.3171/2014.5.peds12614.
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Object Achondroplasia may be associated with compression at the cervicomedullary junction. Determining which patients are at greatest risk for neurological complications of cervicomedullary compression can be difficult. In the current study the authors reviewed their records to determine the incidence and clinical significance of dynamic cervicomedullary stenosis and obstruction of CSF flow along with surgical outcomes following posterior fossa decompression. Methods The authors reviewed 34 consecutive cases involving symptomatic children with achondroplasia undergoing cervicomedullary decompression performed by a single surgeon over 11 years. Of these patients, 29 had undergone preoperative dynamic MRI of the cervicomedullary junction with cine (cinema) CSF flow studies; 13 of these patients underwent postoperative dynamic MRI studies. Clinical outcomes included changes in polysomnography, head circumference percentile, and fontanel characteristics. Radiographic outcomes included changes in dynamic spinal cord diameter, improvement in CSF flow at the foramen magnum, and change in the Evans ratio. Results Patients were predominantly female, with a mean age at presentation of 6.6 years and mean follow-up of 3.7 years (range 1–10 years). All patients had moderate to excellent improvement in postoperative polysomnography, slight decrease in average head circumference percentile (from 46.9th percentile to 45.7th percentile), and no subjective worsening of fontanel characteristics. The Evans ratio decreased by 2%, spinal cord diameter increased an average of 3.1 mm, 5.2 mm, and 0.2 mm in the neutral, flexed, and extended positions, respectively, and CSF flow improved qualitatively in all 3 positions. There were no postoperative infections, CSF leaks, or other major complications. None of the patients undergoing initial foramen magnum decompression performed at our medical center required reoperation. Conclusions Patients with achondroplasia and symptomatic cervicomedullary compression have increased risk of dynamic stenosis at the foramen magnum evident upon dynamic cine MRI. Operative decompression may be offered with low risk of complications or need for reoperation.
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Dawe, Jordan T., and Philip H. Austin. "The Influence of the Cloud Shell on Tracer Budget Measurements of LES Cloud Entrainment." Journal of the Atmospheric Sciences 68, no. 12 (2011): 2909–20. http://dx.doi.org/10.1175/2011jas3658.1.
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Abstract Direct measurements of rates of entrainment into and detrainment from cumulus cloud cores obtained from LES model cloud fields produce values twice as large as those produced from tracer budget calculations. This difference can be explained by two effects: the presence of a shell of air around the cloud cores that is moister than the mean environment and air at the edge of the cloud core that is drier than the mean core, and the tendency for the mean tracer values of the entrained fluid to be greater than the mean tracer values of the cloud shell. Preferential entrainment of shell air that is moving upward faster than the mean shell creates strong vertical momentum fluxes into the cumulus cloud core, thereby making the assumption that cumulus cloud cores entrain fluid with zero vertical momentum incorrect. Variability in the properties of the moist cloud shell has strong impacts on entrainment values inferred from tracer budget calculations. These results indicate that the dynamics of the cloud shell should be included in parameterization of cumulus clouds used in general circulation models.
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Lee, Junsik, and Jae-Hak Lee. "Study on Turbulence Intensity Behavior under a Large Range of Temperature Variation." Processes 8, no. 11 (2020): 1403. http://dx.doi.org/10.3390/pr8111403.
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The turbulence intensity (TI) is defined as the ratio of fluctuation from the standard deviation of wind velocity to the mean value. Many studies have been performedon TI for flow dynamics and adapted various field such as aerodynamics, jets, wind turbines, wind tunnel apparatuses, heat transfer, safety estimation of construction, etc.The TI represents an important parameter for determining the intensity of velocity variation and flow quality in industrial fluid mechanics. In this paper, computational fluid dynamic (CFD) simulation of TI alteration with increasing temperature has been performed using the finite volume method. A high-temperature—maximum 300 degrees Celsius (°C)—wind tunnel test rig has been used as theapparatus, and velocity was measured by an I-type hot-wire anemometer. The velocity and TI of the core test section were operated at several degrees of inlet temperatures at anair velocity of 20 m/s. The magnitude of TI has a relationship with boundary layer development. The TI increased as temperature increased due to turbulence created by the non-uniformities.
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FERRANTE, ANTONINO, and SAID E. ELGHOBASHI. "On the effects of microbubbles on Taylor–Green vortex flow." Journal of Fluid Mechanics 572 (January 23, 2007): 145–77. http://dx.doi.org/10.1017/s0022112006003545.
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The paper describes a numerical study of the effects of microbubbles on the vorticity dynamics in a Taylor–Green vortex flow (TGV) using the two-fluid approach. The results show that bubbles with a volume fraction ∼10−2 enhance the decay rate of the vorticity at the centre of the vortex. Analysis of the vorticity equation of the bubble-laden flow shows that the local positive velocity divergence of the fluid velocity, ∇·U, created in the vortex core by bubble clustering, is responsible for the vorticity decay. At the centre of the vortex, the vorticity ωc(t) decreases nearly linearly with the bubble concentration Cm(t). Similarly, the enstrophy in the core of the vortex, ω2(t), decays nearly linearly with C2(t). The approximate mean-enstrophy equation shows that bubble accumulation in the high-enstrophy core regions produces a positive correlation between ω2 and ∇·U, which enhances the decay rate of the mean enstrophy.
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Vargas Junior, Fernando Miranda de, Luis Maria Bonnecarrère Sanchez, Francisco Stefano Wechsler, Waldmaryan Bianchini, Marcus Vinicius Morais de Oliveira, and Patrick Schmidt. "Influence of corn processing provided in the diet on the ruminal dynamics of dairy steer." Revista Brasileira de Zootecnia 40, no. 2 (2011): 433–40. http://dx.doi.org/10.1590/s1516-35982011000200027.
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The objective of the present study was to evaluate the ruminal dynamics of dairy steer fed diets containing whole corn grains, grains ground into grits or whole grain treated with urea. Thus, six rumen-fistulated animals were kept in confinement and fed diets with similar contents of energy and protein. The diet was formulated with 40:60 roughage:concentrate ratio in the dry matter using sorghum silage as roughage. The experiments followed a 3 × 3 latin square design, with three animals and three periods and they were repeated eith-er two or four times depending on the studied parameter, totaling six or 12 replicates per diet. Corn grain treatment did not affect the pH of the ruminal fluid neither the ruminal degradability of dry matter, acid detergent fiber and cellulose. All diets provided a concentration of amoniacal nitrogen suitable for ruminal microbial growth; however, for animals fed whole corn grain treated with urea, this concentration was significantly lower. Bacterial activity was lower in animals fed diets containing ground corn and they do not differ among animals fed whole corn grain or corn grains treated with urea.
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Landel, Julien R., C. P. Caulfield, and Andrew W. Woods. "Meandering due to large eddies and the statistically self-similar dynamics of quasi-two-dimensional jets." Journal of Fluid Mechanics 692 (January 6, 2012): 347–68. http://dx.doi.org/10.1017/jfm.2011.518.
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AbstractWe investigate experimentally the structure of quasi-two-dimensional plane turbulent jets discharged vertically from a slot of width $d$ into a fluid confined between two relatively close rigid boundaries with gap $W\ensuremath{\sim} O(d)$. At large vertical distances $z\gg W$ the jet structure consists of a meandering core with large counter-rotating eddies, which develop on alternate sides of the core. Using particle image velocimetry, we observe an inverse cascade typical of quasi-two-dimensional turbulence where both the core and the eddies grow linearly with $z$ and travel at an average speed proportional to ${z}^{\ensuremath{-} 1/ 2} $. However, although the present study concerns quasi-two-dimensional confined jets, the jets are self-similar and the mean properties are consistent with both experimental results and theoretical models of the time-averaged properties of fully unconfined planar two-dimensional jets. We believe that the dynamics of the interacting core and large eddies accounts for the Gaussian profile of the mean vertical velocity as shown by the spatial statistical distribution of the core and eddy structure. The lateral excursions (caused by the propagating eddies) of this high-speed central core produce a Gaussian distribution for the time-averaged vertical velocity. In addition, we find that approximately 75 % of the total momentum flux of the jet is contained within the core. The eddies travel substantially slower (at approximately 25 % of the maximum speed of the core) at each height and their growth is primarily attributed to entrainment of ambient fluid. The frequency of occurrence of the eddies decreases in a stepwise manner due to merging, with a well-defined minimum value of the corresponding Strouhal number $\mathit{St}\geq 0. 07$.
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Rey, C., L. J. Gallego, and L. E. González. "Properties of a hard‐core fluid with a Yukawa tail studied by molecular dynamics and the mean spherical approximation." Journal of Chemical Physics 96, no. 9 (1992): 6984–88. http://dx.doi.org/10.1063/1.462854.
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McAllister, T. A., L. M. Rode, K. J. Cheng, and J. G. Buchanan-Smith. "Effect of formaldehyde-treated barley or escape protein on the ruminal environment and digestion in steers." Canadian Journal of Animal Science 72, no. 2 (1992): 317–28. http://dx.doi.org/10.4141/cjas92-039.
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Six Holstein steers fitted with ruminal and duodenal cannulae were fed three diets: formaldehyde-treated rolled barley (0.11% wt wt−1) with canola meal (FTB); untreated rolled barley supplemented with corn distillers' grain and fishmeal (EPB); and untreated rolled barley with canola meal (CON). Foam production from ruminal fluid did not differ among diets. Mean viscosity of ruminal fluid from steers fed FTB was lower (P < 0.02) than rumen fluid from steers fed CON. Ruminal fluid pH of steers fed FTB was lower 2 h after feeding than in steers fed the EPB or CON diets. FTB led to lower (P < 0.02) ruminal ammonia concentrations 1 and 2 h after feeding and lower (P < 0.1) plasma urea nitrogen concentrations 4 h after feeding compared to EPB or CON diets. FTB and EPB tended to lower the ruminal concentration of volatile fatty acids (VFA) associated with microbial amino acid metabolism. Intake, ruminal and postruminal digestion of DM, OM, starch and NDF were not influenced by diet. While EPB had no effect on total tract digestion, FTB increased (P < 0.1) total tract digestibility of starch and decreased (P < 0.1) the digestibility of NDF. EPB increased (P < 0.05) the supply of dietary protein and decreased the supply of microbial protein reaching the small intestine. FTB did not increase the amount of total nitrogen or starch reaching the small intestine of steers. Key words: Cattle, escape protein, starch, formaldehyde, barley
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Shingne, Prasad S., Robert J. Middleton, Dennis N. Assanis, Claus Borgnakke, and Jason B. Martz. "A thermodynamic model for homogeneous charge compression ignition combustion with recompression valve events and direct injection: Part I — Adiabatic core ignition model." International Journal of Engine Research 18, no. 7 (2016): 657–76. http://dx.doi.org/10.1177/1468087416664635.
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This two-part article presents a model for boosted and moderately stratified homogeneous charge compression ignition combustion for use in thermodynamic engine cycle simulations. The model consists of two components: one an ignition model for the prediction of auto-ignition onset and the other an empirical combustion rate model. This article focuses on the development and validation of the homogeneous charge compression ignition model for use under a broad range of operating conditions. Using computational fluid dynamics simulations of the negative valve overlap valve events typical of homogeneous charge compression ignition operation, it is shown that there is no noticeable reaction progress from low-temperature heat release, and that ignition is within the high-temperature regime ( T > 1000 K), starting within the highest temperature cells of the computational fluid dynamics domain. Additional parametric sweeps from the computational fluid dynamics simulations, including sweeps of speed, load, intake manifold pressures and temperature, dilution level and valve and direct injection timings, showed that the assumption of a homogeneous charge (equivalence ratio and residuals) is appropriate for ignition modelling under the conditions studied, considering the strong sensitivity of ignition timing to temperature and its weak compositional dependence. Use of the adiabatic core temperature predicted from the adiabatic core model resulted in temperatures within ±1% of the peak temperatures of the computational fluid dynamics domain near the time of ignition. Thus, the adiabatic core temperature can be used within an auto-ignition integral as a simple and effective method for estimating the onset of homogeneous charge compression ignition auto-ignition. The ignition model is then validated with an experimental 92.6 anti-knock index gasoline-fuelled homogeneous charge compression ignition dataset consisting of 290 data points covering a wide range of operating conditions. The tuned ignition model predictions of [Formula: see text] have a root mean square error of 1.7° crank angle and R2 = 0.63 compared to the experiments.
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Hsu, Chia-Wei, Jianjun Yin, Stephen M. Griffies, and Raphael Dussin. "A mechanistic analysis of tropical Pacific dynamic sea level in GFDL-OM4 under OMIP-I and OMIP-II forcings." Geoscientific Model Development 14, no. 5 (2021): 2471–502. http://dx.doi.org/10.5194/gmd-14-2471-2021.
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Abstract. The sea level over the tropical Pacific is a key indicator reflecting vertically integrated heat distribution over the ocean. Here, we use the Geophysical Fluid Dynamics Laboratory global ocean–sea ice model (GFDL-OM4) forced by both the Coordinated Ocean-Ice Reference Experiment (CORE) and Japanese 55-year Reanalysis (JRA-55)-based surface dataset for driving ocean–sea ice models (JRA55-do) atmospheric states (Ocean Model Intercomparison Project (OMIP) versions I and II) to evaluate the model performance and biases compared against available observations. We find persisting mean state dynamic sea level (DSL) bias along 9∘ N even with updated wind forcing in JRA55-do relative to CORE. The mean state bias is related to biases in wind stress forcing and geostrophic currents in the 4 to 9∘ N latitudinal band. The simulation forced by JRA55-do significantly reduces the bias in DSL trend over the northern tropical Pacific relative to CORE. In the CORE forcing, the anomalous westerly wind trend in the eastern tropical Pacific causes an underestimated DSL trend across the entire Pacific basin along 10∘ N. The simulation forced by JRA55-do significantly reduces the bias in DSL trend over the northern tropical Pacific relative to CORE. We also identify a bias in the easterly wind trend along 20∘ N in both JRA55-do and CORE, thus motivating future improvement. In JRA55-do, an accurate Rossby wave initiated in the eastern tropical Pacific at seasonal timescale corrects a biased seasonal variability of the northern equatorial countercurrent in the CORE simulation. Both CORE and JRA55-do generate realistic DSL variation during El Niño. We find an asymmetry in the DSL pattern on two sides of the Equator is strongly related to wind stress curl that follows the sea level pressure evolution during El Niño.
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Radchicov, V., V. Tzai, A. Kot, et al. "Rumen cannulation of young cattle depending on protein diet." Tehnologìâ virobnictva ì pererobki produktìv tvarinnictva, no. 2(150) (December 17, 2019): 93–104. http://dx.doi.org/10.33245/2310-9289-2019-150-2-93-104.
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An experiment has been carried to determine the degradable and non-degradable protein content in grass and concentrated feed and its influence on operated sire rumen cannulation of black-and-white breed (with body weight of 120–160 kg). The grass chemical composition and concentrated feed research shows that there is a wide range of crude protein content and its degradable and non-degradable fractions. The level of crude protein in concentrated feed varies from 96 g (barley grain) to 380–383 g (extruded lupine grain and rapeseed meal). The amount of degradable protein is 81 (barley grain), 303 g (rapeseed meal). Degradability of crude protein ranges from 57 % (extruded rapeseed) to 84–86 % (barley and wheat grain). The crude protein content in the presented samples of grass feed is 27 (corn silage) – 93 g (cereal hay), degradable protein – from 17–19 (cereal hay and corn silage), up to 38 g (mixed grass), non-degradable – 8 (corn silage, 76 g (cereal hay). The degradable and non-degradable protein ration was 2:7. The crude protein increase in summer and winter calve diet up to 70 % contributes a lower accumulation of ammonia in the rumen fluid (by 19.6–20.6 % ) and activation of VFA synthesis (by 16.5–18.2). It also contributes the increase of the ciliate number (by15,7–15,9), total and protein nitrogen (by 7.2–7.4 and 8.0–12.3 %). Feeding on protein degradability (of 65–60 %) lets the rumen metabolism processes slow down, reduce the microbiota enzyme activity, the protein nitrogen proportion and the ammonia level increasing. According to the analysis results of economic diet indices with different protein fractional composition it has been determined that the ration use with protein degradability of 70 %, and metabolizable energy costs – by 4.0–5.0 % are economically reasonable in summer and winter periods. Key words: concentrated feeds, grain, degradable protein, non-degradable protein, calves.
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YAZGI, Arzu, Vedat DEMİR, and Adnan DEĞİRMENCİOĞLU. "Comparison of computational fluid dynamics-based simulations and visualized seed trajectories in different seed tubes." TURKISH JOURNAL OF AGRICULTURE AND FORESTRY 44, no. 6 (2020): 599–611. http://dx.doi.org/10.3906/tar-1910-15.
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The objective of this study was to compare computational fluid dynamics (CFD)-based simulations and visualized seed trajectories in different seed tubes that can provide seed incorporation into the soil with enhanced seed spacing. The other objective was to determine the relation between the seed trajectories and peripheral speed of the vacuum disk. In order to meet the first objective, 2 different seeds (corn and cotton) and artificial spherical material (Ø10 mm) were tested under laboratory conditions. The seeds and artificial material were released by free fall into the semitransparent seed tubes (seed tubes A and B) from different release points, and their trajectories were recorded using a video camera. For the second objective, corn seeds were used and released from a vacuum-type metering unit equipped with a semitransparent seed tube (seed tube A) at 3 different peripheral speeds of the vacuum disk, as a function of 3 forward speeds of the seeder. For both objectives, the seed tubes were modeled and release of the seeds into the seed tubes was simulated and analyzed using ANSYS Fluent for CFD. The results obtained from the captured video and simulations were compared. As a result of the comparisons, it was found that the seed release point was an effective parameter on both the seed trajectory and seed spacing, since seed bouncing and skating in the seed tube, based on the release point, may occur. The results also showed that the lab tests and simulations were found to be very similar in terms of the seed trajectories and seed spacings. It is believed that this study, using CFD, will be an example and enable the development and design of new seed tubes in order to obtain better seed distribution uniformity.
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Adedeji, O. Y., and A. A. Saka. "In vitro gas fermentation kinetics of compounded ration containing graded levels of biodegraded corncob." Nigerian Journal of Animal Production 47, no. 2 (2020): 224–34. http://dx.doi.org/10.51791/njap.v47i2.131.
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Cob regarded as a waste product, constituting source of environmental pollution could be utilized as an energy source in feed formulation if properly processed and harnessed through fungal degradation. Hence, this study was designed to evaluate the nutritive value of biodegraded corncob meal based diet using in vitro gas production technique. Aspergillus niger was isolated and sub-cultured to obtain a pure culture. Degraded corn cob meals(DCCM) of four dietary treatments were prepared to include: T (0% DCCM which served as 1 the control), T (15% DCCM), T (30% DCCM) and T (45% DCCM). Each diet sample 2 3 4 (200mg) was incubated in buffered rumen liquor for 48 hours and gas volume was estimated using established in vitro gas production models. Amount of gas volume produced was determined every 3 hours for 48 hours of incubation in buffered rumen fluid. After 48 hours ofincubation, methane gas produced was estimated and determined in triplicates. The proximate composition of Aspergillus niger biodegraded corn cob indicated that Aspergillus niger improved the nutritive value of the corn cob. Untreated corn cob meal was lower in nutritive values when compared with treated corncob meal with crude protein, crude fibre and ash values ranging from 6.88 to 9.78%, 32.68 to 26.37% and 2.87 to 2.88% respectively.The proximate composition of the dietary treatments showed that the crude protein varied from (11.67-12.67%), crude fibre (10.94-21.56%), ether extract (2.12-4.88%), ash (6.48- 9.44%) and nitrogen free extract (58.17-62.99%). Results obtained for volume of gas (35.960-72.770mL/200mgDM) produced in time “t” denoted by (b) were significantly different (P<0.05) across the dietary treatments. However, rate of gas production (0.0297- 0.0425mL/hr) and time between incubation and gas production (2.083-2.683hr) were not significantly different (P>0.05) across the dietary treatments. Cumulative gas volumeproduction at 24 hours were significantly (P<0.05) influenced by different inclusion levels of DCCM with values obtained ranging from T (15.33 ml/gDM) to T (35.33 ml/gDM). There 4 3 were significant differences (P<0.05) across the dietary treatments. The post estimated parameters ranging from metabolisable energy (4.96-7.74MJ/Kg DM), organic matter digestibility (37.98-58.03%), short chain fatty acids (0.31-0.78μmol), Methane estimate (3-8 ml/200mgDM) and Carbon dioxide estimate (10-30 ml/200mgDM). It can be concluded that 30% DCCM based diet had the potential of meeting the nutritional needs as smallruminant livestock feeds, if properly biodegraded and incorporated into feeds.
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Vasilachi, A., S. Pop, C. Dragomir, M. Vlassa, and M. Filip. "The influence of replacing slow with rapid starch in growing rams’ diets on the level of rumen microbial proteosynthesis." Biotehnologija u stocarstvu 26, no. 5-6 (2010): 339–46. http://dx.doi.org/10.2298/bah1006339v.
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The objective of the study was to estimate the level of microbial proteosynthesis in sheep, following the replacement of a classical ingredient (corn) with a rapidly fermentable energy source (barley), when protein ingredient of the compound feed is highly degradable (rapeseed meal).The diets were tested on two groups of four Merinos rams each, weighing 50-55 kilos. Regular procedure for in vivo digestibility tests was used and urine was collected for determination of purine derivatives concentrations. The consumption of the two diets led to similar nutritional supplies: 1.26-1.29 MFU, 124-129 g IDPN, 112-118 g IDPE; the groups being distinguish only in terms of the dynamics of energy availability at the ruminal level. The amount of purine derivatives excreted in urine were 12.58 mmols/day in the corn group and 9.49 mmols/day in the barley group; consequently, the rumen microbial proteosynthesis was estimated at 43.11 g IDMP/day for the corn group and 31.3 g IDMP/day for the barley group (P=0,396). It is concluded that the effect of synchronizing the energy and protein dynamics in barley group was counteracted by the fact that energy and protein availability were limited to the first hours after administration of the compound feed, when the capacity of the ruminal microorganisms to grow was probably exceeded. In order to maximize their growth potential, it is necessary to extend the period of synchronized ruminal availability of energy and protein.
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Lin, Mark, and Periklis Papadopoulos. "ANumerical Uncertainty in Parallel Processing Using Computational Fluid Dynamics as Example." Athens Journal of Τechnology & Engineering 8, no. 2 (2021): 169–80. http://dx.doi.org/10.30958/ajte.8-2-3.
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Computational methods such as Computational Fluid Dynamics (CFD) traditionally yield a single output – a single number that is much like the result one would get if one were to perform a theoretical hand calculation. However, this paper will show that computation methods have inherent uncertainty which can also be reported statistically. In numerical computation, because many factors affect the data collected, the data can be quoted in terms of standard deviations (error bars) along with a mean value to make data comparison meaningful. In cases where two data sets are obscured by uncertainty, the two data sets are said to be indistinguishable. A sample CFD problem pertaining to external aerodynamics is copied and ran on 29 identical computers in a university computer lab. The expectation is that all 29 runs should return exactly the same result; unfortunately, in a few cases the result turns out to be different. This is attributed to the parallelization scheme which partitions the mesh to run in parallel on multiple cores of the computer. The distribution of the computational load is hardware-driven depending on the available resource of each computer at the time. Things, such as load-balancing among multiple Central Processing Unit (CPU) cores using Message Passing Interface (MPI) are transparent to the user. Software algorithm such as METIS or JOSTLE is used to automatically divide up the load between different processors. As such, the user has no control over the outcome of the CFD calculation even when the same problem is computed. Because of this, numerical uncertainty arises from parallel (multicore) computing. One way to resolve this issue is to compute problems using a single core, without mesh repartitioning. However, as this paper demonstrates even this is not straight forward. Keywords: numerical uncertainty, parallelization, load-balancing, automotive aerodynamics
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Bottani, Eleonora, Gino Ferretti, Michele Manfredi, and Giuseppe Vignali. "Modeling and Thermo-Fluid Dynamic Simulation of a Fresh Pasta Pasteurization Process." International Journal of Food Engineering 9, no. 3 (2013): 327–39. http://dx.doi.org/10.1515/ijfe-2013-0036.
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AbstractThis work aims to analyze and predict the thermal pasteurization process for two types of fresh pasta, by means of computational fluid dynamic (CFD) simulation. The types of pasta considered are “ravioli” filled of meat and “orecchiette”, without filling. Thanks to many studies on pasta properties, some parameters, such as thermal conductivity and heat capacity, are previously determined for both products. CFD simulations are, thus, performed using ANSYS CFX code version 14.5 in a transient state (after 150 s for ravioli and after 45 s for orecchiette), to evaluate the pasteurization temperature and the P-value reached on the surface of the orecchiette and at the core of the ravioli, as a function of the process time. The heat exchange takes place in a pasteurization tunnel by means of water vapor at ~371 K. Experimental tests are finally performed to validate the simulation model of heat exchange. Results show a good agreement between the simulated results and the real pasteurization process and confirm the potential usefulness of the simulation model to evaluate the process performance.
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Dong, Wenhao, Yi Ming, and V. Ramaswamy. "Projected Changes in South Asian Monsoon Low Pressure Systems." Journal of Climate 33, no. 17 (2020): 7275–87. http://dx.doi.org/10.1175/jcli-d-20-0168.1.
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AbstractMonsoon low pressure systems (MLPSs) are among the most important synoptic-scale disturbances of the South Asian summer monsoon. Potential changes in their characteristics in a warmer climate would have broad societal impacts. Yet, the findings from a few existing studies are inconclusive. We use the Geophysical Fluid Dynamics Laboratory (GFDL) coupled climate model CM4.0 to examine the projected changes in the simulated MLPS activity under a future emission scenario. It is shown that CM4.0 can skillfully simulate the number, genesis location, intensity, and lifetime of MLPSs. Global warming gives rise to a significant decrease in MLPS activity. An analysis of several large-scale environmental variables, both dynamic and thermodynamic, suggests that the decrease in MLPS activity can be attributed mainly to a reduction in low-level relative vorticity over the core genesis region. The decreased vorticity is consistent with weaker large-scale ascent, which leads to less vorticity production through the stretching term in the vorticity equation. Assuming a fixed radius of influence, the projected reduction in MLPSs would significantly lower the associated precipitation over north-central India, despite an overall increase in mean precipitation.
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Almeida, Marina de Paula, Marcelo de Andrade Ferreira, João Paulo Ismério Monnerat dos Santos, et al. "PSX-13 Effects of supplementing sugar-based byproducts on ingestive behavior and ruminal fermentation parameters in small ruminants." Journal of Animal Science 98, Supplement_4 (2020): 458–59. http://dx.doi.org/10.1093/jas/skaa278.799.
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Abstract A duplicated 4 × 4 Latin square design evaluated the effects of replacing ground corn grain (GCG) by sugar-based byproducts plus corn gluten feed (SBB-CGF) on ingestive behavior and ruminal fermentation parameters in small ruminants. Four ruminally cannulated wether sheep and four wether goats (72 and 65 ± 2.3 kg BW, respectively) were individually allocated to 8 pens, over 4 periods of 19-d each (12 d adaptation plus 7 d of sample collection) to receive a diet containing 50% roughage (bermudagrass hay; Cynodon sp.) and 50% concentrate (80% GCG, 16% soybean meal, and 4% premix) with 4 levels of inclusion of SBB-CGF in replacement of GCG (0, 33, 66, and 100%, DM basis). Corn gluten feed was used with SBB to maintain the diets isonitrogenous. Ruminal fluid was collected at 0, 2, 4, and 6 h after the morning feeding, whereas ingestive behavior was assessed on the d 12 of each period for 24 h. Resting time linearly increased with greater inclusion levels of SBB-GCF (P = 0.04; 15.6, 15.7, 16.0, 16.8 h/d). Rumination time was greater (P = 0.001), whereas resting time was lower (P = 0.002) for wether sheep vs. goats (6.5 vs. 4.3 h/d and 15 vs. 17 h/d, respectively). Ruminal concentrations of ammonia-N (P = 0.05; 13.3, 13.2, 10.4, and 10.4 mg dL-1), acetate (P = 0.001; 58.9, 49.6, 48.5, and 43.1 mM), and acetate:propionate ratio (P &lt; 0.001; 3.6, 2.4, 2.0, and 1.9 mM) linearly decreased, whereas propionate concentrations (P = 0.01; 17.9, 23.0, 30.6, and 28.8 mM) linearly increased with greater levels of SBB-GCF in the diet. In conclusion, sugar-based byproducts plus corn gluten feed can replace ground corn grain up to 100% in the diets of goats and sheep consuming a 50:50 roughage:concentrate diet without compromising the ingestive behavior and ruminal fermentation parameters.
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ERFLE, J. D., F. D. SAUER, S. MAHADEVAN, and R. M. TEATHER. "RESPONSE OF LACTATING DAIRY COWS TO FORMALDEHYDE-TREATED SOYBEAN MEAL WHEN FED WITH CONTROL OR UREA-TREATED CORN SILAGE." Canadian Journal of Animal Science 66, no. 1 (1986): 85–95. http://dx.doi.org/10.4141/cjas86-010.
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In two experiments, lactating cows (26 in exp. 1; 32 in exp. 2) were fed an 11.3% crude protein (CP) diet, a 14.7% CP diet containing untreated soybean meal (SBM) or a 14.6% CP diet containing formaldehyde-treated SBM (FSBM), all three fed as a complete blended diet with control corn silage (CCS) (exp. 1); a 12% CP diet, a 13.4% CP diet containing SBM or a 13.3% CP diet containing FSBM, all fed as a complete blended diet with urea-treated corn silage (UCS) (exp. 2). In both experiments concentrates and CCS or UCS were mixed (50:50 dry matter) daily and fed ad lib for a 16-wk period. The increase of CP over the low CP negative control by addition of untreated SBM resulted in a significant (P < 0.05) increase in milk production in both experiments. The addition of FSBM had no significant effect. When comparing solids-corrected milk (SCM), addition of SBM, whether treated or not, significantly increased SCM in both experiments. In neither experiment did FSBM improve milk production over untreated SBM. All animals fed CCS lost body weight but there was no difference between treatments. For animals fed UCS the low CP group lost significantly (P < 0.05) more body weight than did the group fed FSBM. Dry matter (DM) intake was significantly (P < 0.05) lower for the FSBM fed group than for the group fed untreated SBM in exp. 1 (CCS). DM intake was significantly (P < 0.05) increased by either FSBM or SBM over the low CP control fed UCS. Milk protein was the only component significantly (P < 0.05) decreased by FSBM in exp. 1. Isobutyric and isovaleric acids were significantly (P < 0.05) lower in rumen fluid of animals on FSBM plus CCS. Rumen microbial protein content seemed to be more adversely affected by FSBM with CCS than UCS. Amino acid content of FSBM and SBM demonstrated that lysine and tyrosine were lost from SBM after treatment with formaldehyde. The lack of a response in milk production to FSBM is discussed in terms of a lysine and tyrosine deficiency for milk protein synthesis and the adverse effect that formaldehyde protection of SBM may have on the rumen microbial population. Key words: Lactation, dairy cows, urea, corn silage, soybean meal, formaldehyde treatment
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Hodges, Kade, Travis R. Whitney, and Shawn Ramsey. "198 Replacing cottonseed meal and sorghum grain with corn dried distillers grains with solubles in lamb feedlot diets: Growth performance and ruminal fluid parameters." Journal of Animal Science 97, Supplement_1 (2019): 74–75. http://dx.doi.org/10.1093/jas/skz053.169.
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Abstract Effects of replacing cottonseed meal (CSM) and sorghum grain with dried distillers grains with solubles (DDGS) in Dorper ram lamb (n = 46) feedlot diets on growth performance and rumen fluid parameter were evaluated. In a randomized design study, lambs were individually fed ad libitum 70.9% concentrate diets for 56 d in individual pens. The positive control diet (CNTL) contained CSM, sorghum grain, and other concentrates, but no DDGS. Four treatment diets were similar to CNTL, but had no CSM which was replaced 0% (0DDGS), 33% (33DDGS), 66% (66DDGS) or 100% (100DDGS) of the sorghum grain. Lambs fed CNTL were compared to 0DDGS and linear and quadratic effects were evaluated within the four DDGS diets. A treatment × day interaction was observed (P < 0.001) for lamb BW, but not for ADG, DMI, or G:F (P > 0.10). Lambs fed CNTL had greater (P ≤ 0.02) BW on d 42 and 56 and greater (P < 0.01) overall ADG and G:F than lambs fed 0DDGS. On d 42 and 56, lamb BW quadratically increased (P ≤ 0.04) as DDGS increased in the diet. Averaged across all days, ADG quadratically increased (P < 0.001) and DMI and GF tended to quadratically increase (P ≤ 0.08) as DDGS increased in the diet. On d 56, ruminal pH quadratically decreased (P < 0.001), acetate linearly increased (P < 0.001) and acetate:propionate tended to linearly increase (P = 0.08) as DDGS increased in the diet. Results indicated that lamb growth performance is enhanced when CSM is used to increase dietary CP (CNTL vs. 0DDGS) and that all of the CSM and up to 66% of the sorghum grain can be replaced by DDGS (66DDGS) without negatively affecting growth performance.
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Huang, Haibo, Zhaoqin Wang, Shao-Chi Pan, et al. "Fungal Pretreatment to Improve Digestibility of Corn Stover for Animal Feed." Transactions of the ASABE 60, no. 3 (2017): 973–79. http://dx.doi.org/10.13031/trans.12042.
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Abstract. Lignin reduces the digestibility of corn stover as animal feed. Fungal pretreatment has proven an effective way to degrade lignin to improve the bioavailability of corn stover. To understand further the dynamics of the fungal pretreatment process, we investigated the effects of three key parameters (i.e., cultivation time, culture inoculum dosage, and sterilization) on pretreatment of corn stover using a white-rot ). Corn stover was inoculated with different dosages of culture and cultivated for 10, 20, and 30 days. The digestibility of the pretreated corn stover was evaluated by both enzymatic hydrolysis and fermentation with rumen fluid. The lignin degradation in corn stover increased from 0.1% to 20.7% between days 10 and 30. Compared to the raw sample, corn stover pretreated with fungi for 30 days had a significantly greater glucose yield (53.8% compared to 23.3%) and xylose yield (37.9% compared to 13.1%) when enzymatic hydrolysis was conducted (p &lt; 0.05). Increasing the culture inoculum dosage from 4 to 16 mL did not affect the digestibility of corn stover (p &gt; 0.05). Fungal-pretreated corn stover had a greater fermentation rate than raw corn stover during the first 8 h. Fungal pretreatment of non-sterile corn stover caused a substantially reduced sugar yield and fermentation rate, indicating that sterilization is an important step before fungal pretreatment. The results of this study provide key information for the future development of fungal pretreatment of corn stover. Keywords: Corn stover, Digestibility, Fungal pretreatment, Enzymatic hydrolysis, In vitro fermentation.
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Deremble, Bruno, and W. K. Dewar. "Volume and Potential Vorticity Budgets of Eighteen Degree Water." Journal of Physical Oceanography 43, no. 11 (2013): 2309–21. http://dx.doi.org/10.1175/jpo-d-13-052.1.
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Abstract Mode waters are a distinctive baroclinic feature of the World Ocean characterized by relatively weak vertical stratification. They correspond dynamically to low potential vorticity (PV). In the North Atlantic subtropical gyre, the mode waters have become known as Eighteen Degree Water. Their dynamics involves air–sea interaction, diapycnal and isopycnal mixing, and subduction. Understanding mode water dynamics is therefore both challenging and important since it connects several aspects of the ocean circulation. Mass and PV budget of the mode water's core, evaluated in a realistic primitive equation North Atlantic model, are used to characterize mode water maintenance. It is shown that the surface PV flux has very little impact on mode water; the surface buoyancy flux in combination with eddy mass flux is the most important control on mode water structure. A mean PV formalism is used to show that the PV and water-mass formation budgets are intrinsically linked. A decomposition of the budget demonstrates the role of the mean PV field in permitting the eddy mass flux to discharge the net formation to the surrounding fluid.
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O'Quinn, P. R., J. L. Nelssen, J. A. Unruh, R. D. Goodband, J. C. Woodworth, and M. D. Tokach. "Effects of feeding modified tall oil and supplemental potassium and magnesium on growth performance, carcass characteristics, and meat quality of growing-finishing pigs." Canadian Journal of Animal Science 80, no. 3 (2000): 443–49. http://dx.doi.org/10.4141/a00-027.
Full textAbstract:
Eighty crossbred gilts (initially 45.9 kg) were allotted randomly to one of four dietary treatments by weight and ancestry. The trial was arranged as a 2 × 2 factorial with two levels of modified tall oil (MTO) (0 or 0.50%) and added K2SO4-2MgSO4 (0 or 2%), equating to daily K and Mg intakes of 10.84 and 7.75 g, respectively. The corn-soybean meal diets were fed in two phases [45.9 to 76.2 and 76.2 to 118.1 kg body weight (BW)], and supplemental K/Mg was added in place of corn for the final 7 d preslaughter (starting at 114.1 kg BW). Dietary treatment did not affect (P > 0.10) average daily gain (ADG), average daily feed intake (ADFI), or gain to feed ratio (G/F). Feeding MTO decreased average backfat (P = 0.05) and increased intramuscular marbling (P = 0.04). Modified tall oil increased (P = 0.02) percentage lean, and K/Mg supplementation lowered (P = 0.04) longissimus muscle glycogen content. Dietary treatment did not affect (P > 0.10) other carcass characteristics or measures of meat quality. Feeding MTO increased plasma glucose (P = 0.05) and decreased (P = 0.10) base excess in the extracellular fluid. Feeding K/Mg decreased (P < 0.10) plasma pH, BUN, and base excess in the whole-blood and extracellular fluid and increased (P < 0.10) ionized Mg++ and lactate. These results support earlier research identifying MTO as a carcass modifier and contributor to meat composition and quality. Potassium and Mg supplementation altered whole-blood profiles and longissimus muscle glycogen content in a manner expected to improve pork quality, although not observed. Key words: Swine, modified tall oil, potassium, magnesium, meat quality
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Cowieson, A. J., H. Lu, K. M. Ajuwon, I. Knap, and O. Adeola. "Interactive effects of dietary protein source and exogenous protease on growth performance, immune competence and jejunal health of broiler chickens." Animal Production Science 57, no. 2 (2017): 252. http://dx.doi.org/10.1071/an15523.
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A total of 672 male 7-day-old broiler chicks were used in a 14-day cage study to evaluate the interactive effects of dietary protein source and exogenous protease on nutrient digestibility and intestinal physiology. Birds were fed a common starter diet from Days 0 to 7 and switched to experimental diets from Days 7 to 21. Four corn-based dietary treatments were arranged in a 2 × 2 factorial arrangement with factors being two major sources of protein [soybean meal (SBM) or canola meal] and diets offered with or without exogenous protease. Bodyweight gain and gain:feed were higher (P < 0.001) in the diets based on SBM than in the diets based on canola meal and protease was more effective (P < 0.05) in enhancing performance in SBM-based diets. Ileal nitrogen digestibility was increased (P < 0.01) by protease use in diets based on both major protein sources. However, ileal digestible energy was increased (P < 0.05) by protease only in the SBM-based diet resulting in an interaction between diet protein source and exogenous protease. Jejunal villus height tended to be higher (P = 0.07) in birds fed diets based on SBM and protease use increased (P < 0.05) crypt depth only in the SBM-free diets resulting in a significant interaction between protein source and protease use. Patterns of gene expression in jejunal tissue suggested that both dietary protein source and exogenous protease influence the expression of genes responsible for mucin secretion, amino acid transport and immune functionality in an age-dependent manner. It can be concluded that SBM may be a more suitable protein source for young broiler chickens than canola meal and that use of canola meal as a major source of dietary protein may have negative implications for performance, nitrogen digestibility and gut health. However, exogenous protease appears to be more compatible with substrates presented by SBM than is the case for canola meal based on advantages conferred in nutrient digestibility and performance. The beneficial effects of exogenous protease may be linked both to enhanced protein and energy digestibility and improved gut morphological characteristics, secretory and absorptive dynamics and immune resilience.
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BRABAZON, J. W., E. PERFECT, C. H. GATES, et al. "SPONTANEOUS IMBIBITION OF A WETTING FLUID INTO A FRACTURE WITH OPPOSING FRACTAL SURFACES: THEORY AND EXPERIMENTAL VALIDATION." Fractals 27, no. 01 (2019): 1940001. http://dx.doi.org/10.1142/s0218348x19400012.
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Spontaneous imbibition (SI) is a capillary-driven flow process, in which a wetting fluid moves into a porous medium displacing an existing non-wetting fluid. This process likely contributes to the loss of fracking fluids during hydraulic fracturing operations. It has also been proposed as a method for an enhanced recovery of hydrocarbons from fractured unconventional reservoirs. Numerous analytical and numerical approaches have been employed to model SI. Invariably, these idealize a fracture as the gap formed between parallel flat surfaces. In reality, rock fracture surfaces are rough over multiple scales, and this roughness will influence the contact angle and rate of fluid uptake. We derived an analytical model for the early-time SI behavior within a fracture bounded by parallel impermeable surfaces with fractal roughness assuming laminar flow. The model was tested by fitting it to experimental data for the SI of deionized water into air-filled rock fractures. Twenty cores from two rock types were investigated: a tight sandstone (Crossville) and a gas shale (Mancos). A simple Mode I longitudinal fracture was produced in each core by compressive loading between parallel flat plates using the Brazilian method. Half of the Mancos cores were fractured perpendicular to bedding, while the other half were fractured parallel to bedding. The two main parameters in the SI model are the mean separation distance between the fracture surfaces, [Formula: see text], and the fracture surface fractal dimension [Formula: see text]. The [Formula: see text] was estimated for each core by measuring the geometric mean fracture aperture width through image analysis of the top and bottom faces, while [Formula: see text] was estimated inversely by fitting the SI model to measurements of water uptake obtained using dynamic neutron radiography. The [Formula: see text] values ranged from 45[Formula: see text][Formula: see text]m to 190[Formula: see text][Formula: see text]m, with a median of 93[Formula: see text][Formula: see text]m. The SI model fitted the height of uptake versus time data very well for all of the rock cores investigated; medians of the resulting root mean squared errors and coefficients of determination were 0.99[Formula: see text]mm and 0.963, respectively. Estimates of [Formula: see text] ranged from 2.04 to 2.45, with a median of 2.24. Statistically, all of the [Formula: see text] values were significantly greater than two, confirming the fractal nature of the fracture surfaces. Future research should focus on forward prediction through independent measurements of [Formula: see text] and extension of the existing SI model to late times (through the inclusion of gravity) and fractures with permeable surfaces.
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Yuji Yasuda, Eric, Erika Tomie Koroishi, Osvair Vidal Trevisan, and Euclides José Bonet. "Evaluation of Permeability Changes in a Carbonate Rock under Carbonate Water Flow." Applied Mechanics and Materials 830 (March 2016): 65–70. http://dx.doi.org/10.4028/www.scientific.net/amm.830.65.
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Carbon dioxide (CO2) injection in reservoirs promotes reactions which depend on rock nature, brine composition, partial pressure of CO2, reservoir temperature and pressure among other conditions. The reactions may cause changes in the petrophysics properties, including porosity and permeability, that are important parameters to the fluid flow. The present study focus on the effects of carbonated brine injection in carbonate rocks similar to pre salt reservoirs. The effects are evaluated through the changes of the rock absolute permeability provoked by the acidic action of the injected fluid. Experiments were designed to detail permeability changes along the length of a long carbonate core using using a coreholder equipped with multiple pressure taps. The experiments were conducted in dynamic regime, at the temperature of 22°C and at the mean pressure of 2,000 psi, at flow rates of 0.5; 1 and 2 cc/min. The results show significant permeability alterations at the different segments of the sample, which are also highly dependent on the injection rate.
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Angus, Doug A., James P. Verdon, Quentin J. Fisher, and J. M. Kendall. "Exploring trends in microcrack properties of sedimentary rocks: An audit of dry-core velocity-stress measurements." GEOPHYSICS 74, no. 5 (2009): E193—E203. http://dx.doi.org/10.1190/1.3183940.
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Rock-physics models are used increasingly to link fluid and mechanical deformation parameters for dynamic elastic modeling. We explore the input parameters of an analytical stress-dependent rock-physics model. To do this, we invert for the stress-dependent microcrack parameters of more than 150 sedimentary rock velocity-stress core measurements taken from a literature survey. The inversion scheme is based on a microstructural effective-medium formulation defined by a second-rank crack-density tensor (scalar crack model) or by a second- and fourth-rank crack-density tensor (joint inversion model). Then the inversion results are used to explore and predict the stress-dependent elastic behavior of various sedimentary rock lithologies using an analytical microstructural rock-physics model via the initial modelinput parameters: initial crack aspect ratio and initial crack density. Estimates of initial crack aspect ratio are consistent among most lithologies with a mean of 0.0004, but for shales they differ up to several times in magnitude with a mean of 0.001. Estimates of initial aspect ratio are relatively insensitive to the inversion method, although the scalar crack inversion becomes less reliable at low values of normal-to-tangential crack compliance ratio [Formula: see text]. Initial crack density is sensitive to the degree of damage as well as the inversion procedure. An important implication is that the fourth-rank crack-density term is not necessarily negligible for most sedimentary rocks and evaluation of this term or [Formula: see text] is necessary for accurate prediction of initial crack density. This is especially important because recent studies suggest that [Formula: see text] can indicate fluid content in cracks.
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Papáček, Štěpán, Karel Petera, Petr Císař, Vlastimil Stejskal, and Mohammadmehdi Saberioon. "Experimental & Computational Fluid Dynamics Study of the Suitability of Different Solid Feed Pellets for Aquaculture Systems." Applied Sciences 10, no. 19 (2020): 6954. http://dx.doi.org/10.3390/app10196954.
Full textAbstract:
Fish feed delivery is one of the challenges which fish farmers encounter daily. The main aim of the feeding process is to ensure that every fish is provided with sufficient feed to maintain desired growth rates. The properties of fish feed pellet, such as water stability, degree of swelling or floating time, are critical traits impacting feed delivery. Some considerable effort is currently being made with regard to the replacement of fish meal and fish oil with other sustainable alternative raw materials (i.e., plant or insect-based) with different properties. The main aim of this study is to investigate the motion and residence time distribution (RTD) of two types of solid feed pellets with different properties in a cylindrical fish tank. After experimental identification of material and geometrical properties of both types of pellets, a detailed 3D computational fluid dynamics (CFD) study for each type of pellets is performed. The mean residence time of pellets injected at the surface of the fish tank can differ by up to 75% depending on the position of the injection. The smallest residence time is when the position is located at the center of the liquid surface (17 s); the largest is near the edge of the tank (75 s). The maximum difference between the two studied types of pellets is 25% and it increases with positions closer to the center of the tank. The maximum difference for positions along the perimeter at 3/4 tank radius is 8%; the largest residence times are observed at the opposite side of the water inlet. Based on this study, we argue that the suitability of different solid feed pellets for aquaculture systems with specific fish can be determined, and eventually the pellet composition (formula) as well as the injection position can be optimized.
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Génin, A., K. Essemiani, C. Lemoine, E. Barbier, and S. Logette. "Impact of hydrodynamics on the precipitation efficiency – application to HARDTAC reactor." Water Science and Technology 56, no. 11 (2007): 101–8. http://dx.doi.org/10.2166/wst.2007.772.
Full textAbstract:
Precipitation of gypsum is studied in a HARDTAC (High-Aspect Ratio, Draft-Tube, Agitated Crystallizer) reactor, which is considered as the core crystallization unit of lots of wastewater treatment systems. Coupling Computational Fluid Dynamics (CFD) and population balance modelling to simulate precipitation can be a useful tool to come to a decision about upstream and downstream units. In the present study, we aim to validate such approach by investigating gypsum precipitation in a HARDTAC pilot unit and comparing experiments results with simulation. Measured nucleation and growth kinetics are used to feed the model. A comparison between experiments and simulations is presented in the case of gypsum precipitation with a given set of operating conditions. Good agreement is obtained for species concentrations, gypsum mass fraction and volumetric mean diameter but some discrepancies still remain between measured and simulated crystal size distribution.
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He, Shanshan, Yi Qian, Wenliang Xue, and Longdi Cheng. "Numerical Simulation of Flow Field in Air-Jet Loom Main Nozzle." Autex Research Journal 19, no. 2 (2019): 181–90. http://dx.doi.org/10.1515/aut-2018-0053.
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Abstract To improve airflow injection capacity of the main nozzle and decrease backflow phenomenon, a new main nozzle structure with two throats is designed. Negative pressure value and negative pressure zone length are first proposed evaluating the strength of backflow phenomenon. Commercial computational fluid dynamic (CFD) code “Fluent” is performed to simulate the flow field inside and outside the main nozzle. Exit velocity increases about 10 m/s in new main nozzle. Airflow core length of the new main nozzle is 35% higher than that of commonly used main nozzle. Smaller negative pressure value and shorter negative pressure zone length mean a weaker backflow phenomenon in the new main nozzle. Bigger air drag force indicates stronger weft insertion ability in the new main nozzle.
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Forte, Erin M., Mary Kimberly Mullenix, Jennifer J. Tucker, Joshua B. Elmore, and Werner G. Bergen. "Conserved forage-based systems for backgrounding weaned beef calves1." Translational Animal Science 2, no. 3 (2018): 272–79. http://dx.doi.org/10.1093/tas/txy063.
Full textAbstract:
Abstract A 45-d backgrounding study was conducted to compare animal performance, forage nutritive value, digestion dynamics, and diet costs of conserved forage systems for weaned beef calves. One hundred and eight weaned Angus × Simmental beef calves (initial BW 279 ± 34 kg) were randomly assigned to one of three diets (n = 3 pens/treatment): 1) free-choice annual ryegrass (RB; cv. ‘Marshall’) baleage and 4 kg of a 50/50 mixture of pelleted soybean hulls and corn gluten feed, 2) free-choice Tifton 85 bermudagrass (BH) and 3 kg of a 50/50 mixture of pelleted soybean hulls and corn gluten feed, or 3) free-choice corn silage (CS; cv. Pioneer P1662YHR) and 2 kg of a 85% cracked corn and 15% cottonseed meal mixture. Diets were formulated to achieve a target gain of 0.9 kg/d based on the NRC (2000) requirement for a 270 kg growing calf. Animal performance (initial BW, final BW, and ADG) was measured on days 0 and 45 of the study. Forage nutritive value and an in vitro digestion trial were conducted to evaluate supplementation effects on forage diet digestion dynamics. Data were analyzed using PROC Mixed in SAS 9.4 as a completely randomized design. Pen was the experimental unit. Mean initial and final BW of the animals did not differ (P = 0.50 and P = 0.99, respectively) across treatments. Calf ADG for RB, BH, and CS diets were 0.61, 0.72, and 0.72 kg/d, respectively, and did not differ across treatments (P = 0.57). Based on these results, these forage options supported a similar level of gain when used for backgrounding beef calves. Forage in vitro DM digestibility differed 48 h after digestion, and BH + 50:50 had greater 48-h digestibility than when unsupplemented, which may be related to complementary forage-supplement interactions. In diets containing RB and CS, digestibility was greater with no supplementation at the 48-h time point. These data support the observation that supplementation type and level influence conserved forage diet digestibility compared with forage alone. The cost of feeding a baleage-based diet in this system was higher ($1.37/d) than CS or BH diets ($1.02 and $0.95/d, respectively). Results suggest that RB baleage-based diets may support a similar level of gain to BH or CS diets in growing beef calves, but supplement type, level, and ration costs should be evaluated when determining cost-effective backgrounding options in the Southeastern United States.
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CAMASSA, ROBERTO, CLAUDIA FALCON, JOYCE LIN, RICHARD M. McLAUGHLIN, and NICHOLAS MYKINS. "A first-principle predictive theory for a sphere falling through sharply stratified fluid at low Reynolds number." Journal of Fluid Mechanics 664 (October 12, 2010): 436–65. http://dx.doi.org/10.1017/s0022112010003800.
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A sphere exhibits a prolonged residence time when settling through a stable stratification of miscible fluids due to the deformation of the fluid-density field. Using a Green's function formulation, a first-principles numerically assisted theoretical model for the sphere–fluid coupled dynamics at low Reynolds number is derived. Predictions of the model, which uses no adjustable parameters, are compared with data from an experimental investigation with spheres of varying sizes and densities settling in stratified corn syrup. The velocity of the sphere as well as the deformation of the density field are tracked using time-lapse images, then compared with the theoretical predictions. A settling rate comparison with spheres in dense homogeneous fluid additionally quantifies the effect of the enhanced residence time. Analysis of our theory identifies parametric trends, which are also partially explored in the experiments, further confirming the predictive capability of the theoretical model. The limit of infinite fluid domain is considered, showing evidence that the Stokes paradox of infinite fluid volume dragged by a moving sphere can be regularized by density stratifications. Comparisons with other possible models under a hierarchy of additional simplifying assumptions are also presented.
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Bajracharya, Tri Ratna, Rajendra Shrestha, and Ashesh Babu Timilsina. "A Methodology for Modelling of Steady State Flow in Pelton Turbine Injectors." Journal of the Institute of Engineering 15, no. 2 (2019): 246–55. http://dx.doi.org/10.3126/jie.v15i2.27674.
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Pelton turbine is a high head-impulse type turbine. The high-speed jet strikes the symmetrical semi ellipsoidal buckets, thus transferring the momentum within short period of time, impulse. The conversion of potential energy of water to kinetic energy in the form of jet is done by a nozzle with internally fitted spear or needle, the assembly in known as injector. The jet quality includes but is not limited to jet velocity, velocity distribution ‘velocity profile’, core location etc. In this study, the modeling of flow in Pelton turbine injector is done by commercial Computational Fluid Dynamics (CFD) solver on a three-dimensional flow domain. The results obtained from CFD modelling are then compared against the experimental observations and previously published literatures. The jet streamline, jet velocity profile and jet core location are then studied. As observed experimentally, the mean jet diameter reduces as the nozzle opening decreases. In addition, like the experimental observations, the jet first contracts and then expands. The diameter of the contraction is then normalized with nozzle exit diameter and is plotted for both experimental observations as well as the results of the numerical simulation. The maximum error between experimental and numerical analysis of jet contraction is 20%. The jet core is located at region axially ahead of needle tip.